High pressure pumps in fuel injection systems are used to load a fuel with a high pressure, the pressure, for example in the case of gasoline internal combustion engines, lying in the range from 250-400 bar and, in the case of diesel internal combustion engines, lying in the range from 2000 bar-2500 bar. The higher the pressure generated in the respective fuel, the lower the emissions which are produced during the combustion of the fuel in a combustion chamber.
To achieve the high pressures in the respective fuel, the high pressure pump is typically configured as a piston pump with the piston driven by a roller plunger. The roller plunger has a roller in contact with a cam surface of a cam of a camshaft driven by the internal combustion engine. Here, a rotational movement of the camshaft is converted via the roller plunger into a translational movement and is transferred to a piston of the high pressure pump.
During the conversion of the rotational movement of the camshaft into a translational movement, both axial forces and lateral forces are transmitted to the roller plunger by way of the cam surface. The lateral forces can lead to tilting of the roller plunger within a plunger guide in the high pressure pump.
Attempts to manage said tilting seek to maintain a ratio of a roller plunger length L to a roller plunger external diameter D within the range of L/D>1. Furthermore, if a roller plunger axis is arranged offset toward the axis of the camshaft, a contact angle between the roller plunger and the cam surface can be decreased, in order to reduce the resulting lateral forces. Here, the geometry and also the center of mass of the roller plunger are chosen in a way that, as far as possible, no offset with respect to the roller plunger axis is produced, which roller plunger axis is arranged offset toward the axis of the camshaft.
In addition, there are also arrangements which provide an anti-rotation safeguard in order to avoid rotations of the roller plunger in the roller plunger guide.